Our larger objective is to understand the forces that hold alpha- helices in that conformation and the forces that hold one helix to another in protein double helices. Our approach is: to remove or characterize the polydispersity of certain alpha-helix-forming synthetic polypeptides in order to render their physical properties, including the helix-coil transition, more interpretable; to explore conditions under which these synthetic polymers might form double alpha-helices; to investigate the helix-coil transition in the protein double helices; to seek conditions under which single, protein helices might form; and to produce and examine double helices, i.e. clam paramyosin - lobster paramyosin, paramyosin-tropomyosin, tropomyosin-synthetic polypeptide hybrids.